A conventional pharmaceutical injection device comprises a main body case having an injection needle extension/retraction opening; a pharmaceutical syringe mounting portion provided inside the main body case; a pharmaceutical syringe mounted to the pharmaceutical syringe mounting portion; a piston capable of moving relative to the pharmaceutical syringe mounting portion; a drive mechanism for driving the piston; a controller that is electrically connected to the drive mechanism; and an orientation sensor that is electrically connected to the controller.
Also, the pharmaceutical syringe has a cylinder, a distal end gasket provided on the distal end side within the cylinder, a push-in gasket provided on the rear end side within the cylinder, a separation gasket provided in the middle within the cylinder, a solid pharmaceutical housed in the cylinder between the distal end gasket and the separation gasket, a liquid pharmaceutical housed in the cylinder between the push-in gasket and the separation gasket, and a bypass that sticks out in the outer peripheral direction of the cylinder at a portion of the cylinder between the distal end gasket and the separation gasket (see Patent Literature 1, for example).
The controller uses the drive mechanism to push the push-in gasket to the distal end gasket side with the piston after detection of the orientation position by the orientation sensor (see Patent Literature 2, for example).